oooh, this is fabulous because I have a similar problem! We are going with a bold yellow…it will depend on the bridesmaids dresses, as to how bold…but definitely not a buttercup yellow…and I want to incorporate a slate/smokey grey…but as for a third and fourth, I thought cream/white, black and a sagey/moss green. The green would mostly be highlighted in our flowers I think…

Our venue luckily doesnt require alot of decorating, it space kind of speaks for itself…which I lucked out on.

Maybe consider green and cream to go with it…its all I could come up with thus far! 🙂

The first colors that popped into my mind would be white/cream and either a sagey green or a bright green! Both would look FAB with yellow and gray! But really yellow and gray can go with almost any color. Stick with the colors closest to yellow on the color wheel (oranges, greens, reds, and even light blues) and you’ll be ok. Greens would be the easiest to incorporate as they’ll be in the stems of your flowers.

since you’re pretty set on those two colors, you might want to chose another that just naturally compliments them, instead of something crazy. i agree with Brushetta…mossy green could be fabulous! And would be brought out in the flowers! Or how about a navy? Good luck!